The present invention relates generally to adhesive labels and transfer adhesive sheet and more particularly to a method and apparatus for producing sheet of adhesive labels and precut areas of transfer adhesive.
Transfer adhesive tabs are used for applying a predetermined shape of adhesive for the binding of two objects. Generally, the transfer adhesive tabs are fabricated as sheet material that includes an adhesive protected by two liners, each being positioned on either side of the adhesive. For example, transfer adhesive tab sheet is available for applying preformed areas of transfer adhesive to finger nails for securing false plastic finger nails thereto.
The known methods of producing such sheet material of transfer adhesive tabs include the steps of applying an adhesive layer to the entire surface of a first liner material and then laminating a second liner material so as to sandwich the adhesive layer between the liners. The next step is to die cut through one liner material, considered the top liner material, and the transfer adhesive layer without die cutting through the other liner material, considered the bottom liner material, to thereby form the tabs which include the predetermined areas of transfer adhesive and the corresponding remaining top liner material laminated thereto. The waste material left between the tabs, including the unwanted adhesive and unwanted top liner material, is then removed leaving the bottom liner material and the predetermined areas of transfer adhesive covered by top liner material that does not extend beyond such predetermined areas.
The sheet material may be manufactured in small pieces or in a long piece formed into a roll. Roll material is generally manufactured in a continuous process which is typically more economical than making small pieces such as letter or A4 size or other sizes. The roll can be cut into such smaller sizes if desired.
A similar process may be used to produce sheet material of labels. The labels are intended to be adhered to an object. Thus, (in contrast with the transfer adhesive tab arrangement) the adhesive and the material forming the liner (referred to as the substrate for labels) that will form the label and that will be printed on are chosen so that the substrate will not easily peel away from the adhesive.
This process suffers from a number of disadvantages. First, die cutting through the adhesive without die cutting through the bottom liner is a sensitive and precise operation. Variations in the thickness of the adhesive will result in either the adhesive not being complete die cut or the bottom liner being die cut to some extent.
Another disadvantage of this process is the difficulty presented in stripping away the waste material without removing the die cut transfer adhesive tabs. There is a tendency, due to the presence of the adhesive, for the tabs to stick to the die. This tendency is aggravated if, due to variations in the adhesive thickness, the adhesive is not completely cut through.
In the event that, due to variations in the adhesive thickness or otherwise, the bottom liner material is cut by the die, it becomes difficult to separate the adhesive from the cut bottom liner material without destroying the integrity of the adhesive.
Another difficulty arising when the desired adhesive thickness on a particular substrate is only needed for a small job. Substrate is typically purchased precoated. Orders of special precoated adhesive substrate combinations must be bought in minimum quantities or for escalated prices. Some desired adhesive thicknesses may not be available. Typically, the maximum adhesive available on precoated sheets is five thousandths of an inch. The normal thickness is one-half of one thousandth of an inch.